SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f95f9245cd55b2984a940d9ef496e79ad4d862339fd6508fd49d218daf57818c' 
  AND token = 'eAe0yeLcOQPuLn4ZWCYlNvlBouEnN0as3tiVBvX8NO4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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