SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950231a32bf19128ffc3390e155786132a6d78734c66e859c6933f7bf463ed4b' 
  AND token = 'MqldMyLaBBWl7G/VpUtEeXpmM4tiMY91EyLbx1iDki0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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