SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee8f7609edf3c6a305cd1c53a8316cb50fcfd0b5252d93462d274b38a9628af9' 
  AND token = 'DpCCgv6whba7KS57pZ2vqJhRfmxHQ/mxmw5jquNvSnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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