SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b854754a80490826984610a3703ba962912edb55fdc37ca1213814f68b81c9dd' 
  AND token = 'c/t+t8udztqhA57bU8bPYYq9/dmDBrHLlS/hTdmpQ7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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