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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fa85c5c903d6ff804daf88d2bc5d1b0e7b76cdb4bf9086f5f0859d4c4955c9c' 
  AND token = 'mt6u+ADqGiU60kERgVspWumpfpRjPp+U1ZTB4pcT+YY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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