SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1539d78f73eaf00eea1e39fdb9d8e93347214167a08bae823279af0618c83fb' 
  AND token = 'TE9RJtS2Ptxx6C73Genz7PEdwD6/Ia9vz22Ei/wx/wQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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