SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c754b935dc666861faa85676a2f65e26ac171211c4f256387ec608d9226219cc' 
  AND token = 'QN0DFkmxopmVo+lQMfjCFrbkqX1iQJWmu7ROQJaNk2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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