SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ac1f06664d5a6a0e88965ed170fd9ddae54a3cde79c2fc19645a2731bff4666c' 
  AND token = 'retLRih/fNic3id8RlGJXbKFXIE6AZoGDTeSm0Gj+OI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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