SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e3edb7b0da185f8f8a934de9546dd2262843e5ac2ee18b74ca317a49a814bb8f' 
  AND token = 'RxlfQLEgaxZrnS4WrgjBwxrWapDnYCFr9yfObIIxEvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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