SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c3fffa48eaadfbd374eb0a77b820100a39e911c98adb5821272abc2384f43e85' 
  AND token = '0Mhn7rEfF3QW9DHplVS4ZdmZefKDXnZdqufWyCck30o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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