SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2d9da606bc68830db1d7c7b12c11f5a7b649577eb7a7633e6f28f57e1e0a9f' 
  AND token = 'PshtMl2aNY4xEscaX/DCkpyJ4wktddZra70DoUIQGfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}