SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '443f0f95c45d9962707e19d1fcfce0a5251b4af4eef005ca42d889dd5cc4d483' 
  AND token = 'uZFujYi+T4mJVq5xijH/ne3PkaOfB8HN2MjLgPwW+hE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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