SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e28452a8e1fca83fc31fa72973a866532fb12abea16a0c4a24855af0d263e45a' 
  AND token = 'x3E8rSH0YtALeyFjwmdxl5fnpWL8aM63Ddj+XWKfwa4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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