SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '758ed84ec6a78e3634a01bf6f6096ec8969503b269701cf22a90ca61605d5a3f' 
  AND token = 'dHaDbExrEeQ+arOqnE68866KyFBXwtpXoR8BKjHmg3g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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