SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c192a23e3f82bdae3c747220ff6db9da44641cd44653d9ac4dc218eab414ca21' 
  AND token = 'GiOlvznTCX89sNoOq1CDgMU4jJ+c/emuzYpdPm+UmRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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