SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6992e065867ed096c9ff97a4948148fbde0aaf9922495a6cab44dd208e554c4d' 
  AND token = 'qtGXQhWGNzKkhswhEFaGh9Ppl+KhTg0FmTq2O+fBc2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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