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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc50df8a39aca39c5da87b5feebb4dd3dae33896cc724e046b60dcfcfd5cbd45' 
  AND token = 'HLp1gbVTueKmKqcwLV//ATCHwjAiZ5BQ35a+QmOp0f0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}