SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f51db910fddacd01b20fe8a1f9affc104754ec8be0bf32f675827b984ecc9af7' 
  AND token = 'piPlfY0YclSMq1AF/IozR0qIv13qclG80+X2/CXWokE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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