SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d6eb96ac97080b2dd22729aac0bf6d12e194258cee3c29b9dc6c98f58d4c7d0' 
  AND token = '7fqJKBo5U0xDstSi1ndVNJoRXyOnx4EMRDToVM5wJJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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