SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad9d98f43b6ce361d991a2aa21f8ab3dc92dff77176b652035168e292730c185' 
  AND token = 'OtGYrg44cl2qHg3JLYJUGvbwEFYCRKE6KNiLSDM/+LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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