SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70239816af09e5729bdc63f5df419ea6eba9cfe6748d369a1c3f89d3e1c373cc' 
  AND token = '2NE7rTId4LaZH8zPcbF/MmQrczr++faGVosq2DuT+rA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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