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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e71dd01a3a2b7e700a2e92ad22ec1df89f0cfef2f595e75efa4478e8a7bf4dc' 
  AND token = 'Ui9hsmMUdpuXc1rBcqsQy3jMKa4a2Xb7zGkuI1Zo/bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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