SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34912e2f87d52fb6439b45f2b5e965b988afdb1a823633b318ff8b1701e78b26' 
  AND token = '0t6tmFXlbvYW1JxzKcX8mcU4EQg9xvJQ0wDjBXKJQ2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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