SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d8664e38d7e36d12ac0ddae4d5027ce9eaf9bc0f435217d25bda9e93a9ead8' 
  AND token = 'PGsfzkFOHbZ20IaBvIfe6FSzrZIwYoaJ42RB3wSVjSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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