SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bed9127d9125e1d092c5f6df1c321cdbea080b11af291e01f683d173835f36da' 
  AND token = 'okojt1mXr2goeC9ExTesOmmWdOQmS7m6oxnaG4YLwK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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