SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '424e7f90a8ac1fd5863fa8d49305ac43a4f76ff58be742fe1e6f08b390ed5443' 
  AND token = 'h7jUksi4kOXSvwLW/qGPzHZljsP2vMYBK9LMiB6jC8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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