SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c570f37e511f4128474cf58014d29b8a6e318e09f2275fa0ab928a335e18e567' 
  AND token = 'zus/bKQUBC1h1eGQYkCjFxtQpXOvCHZUuRuwxOX1sZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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