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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9eb9e2a1fed82c8d35b51c3cbcd421d401ac4a5e1dac22a9f16f83a9a153c795' 
  AND token = 'KLdPHb3n18jGTHpfBxsLrPzxnGG1buKxm6VNfyeFY/A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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