SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bf9291ffd4ebe4a40a2c3720a27be9933454cdc7901106853eb4966084bfa5e' 
  AND token = 'OZmPrynlmTE3XYIDIZEaogadH/0Kd+IUo4h9W7NERNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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