Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51ec1f8def8ba602beb25ef9b0d7c6bfc7350fe39dd2d0523af2fc6b98e38a7b' 
  AND token = 'AgFDaPjeKXOnkDjvrws1G7taTi2cNeWfNQAFtgENWmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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