SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '147607828223c09c9f0e87556051494bebe29d895ba29d661fda498c9b7641c1' 
  AND token = '7lzmyYvYN5xu5VXFAvcU6p3k500xMHmixM3YjqrLqdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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