SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bb4eeaf0eb57cc800c97c21e23d338597901d75a7d4f8a2aacebe1fb3988d25' 
  AND token = 'wloKql7ltgquq6OWM0H7OYbiCh/XZZ3VmGUgm0W2ktQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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