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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7f01ca0c2f20dda3fe841e30fc41dd15815e43dd23930ca4c8ca40b4f0f9a43' 
  AND token = '4z/PiePedN1QZ0Flz6mmRRNdiar8MrGwXLLrvKCGOxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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