SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f58af04eaa3a22bca79101af6bab8a5519a85973fe2bdd3d3615f1f794f6c18' 
  AND token = 'acsKzQs6Fnav6A4LCBxv+pxJHBZrtpwkBBuJ/BkIo5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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