SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '154c1405ccff5aa13fc15c849ea0d459faceda45d30f92e7beea58d23cbf20da' 
  AND token = 'l0QvmiQ7RP4BSbestnVvwsuppaIwYPGgiXe7CPtOn54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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