SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b17235ce8bc173f13410db12674e68a77ac19df95c1b5b6f2021fd44baf5bd76' 
  AND token = 'VuDrCVrbsurcUqhwSzQxpV9ntHuCPYT3hFfAB5nMVEE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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