SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7ca555cdcefe83abf3555542d41d6b61480d5c8cc36a35af08e72b5e43fc9b56' 
  AND token = '5RV1Gm/zvlH2jfguAN/C6b6e7wc1TznqnWKeIBYXuM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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