SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '78d46d35a315f22bcd041bc00165b7d8625dddb02cde12e4349472e8b19c17fd' 
  AND token = '5r50AnnARs7EYypFjuJgWzrzQr83LDbuI2Fv/a3ErV4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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