SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6052075a9800cb7d563f65fda10b4ca49f94d1ebe8372d1522798fb0e23aa16' 
  AND token = '6M1J4Q6ubqImnIbKyq2XIXeHIKEl47LedUB6btpewis=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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