SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5fa0619ea4875eb813fd0c141df8aa690963029d2b0b885146ddbff26e6948b' 
  AND token = 'ThsJQ7UOP34Z+BAwlpInVdN7lLrikNiv+CzjWqsOuzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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