SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9543bc27d366c876856813f745efd9337ec904173d3ae8f6fc7f0576460aee94' 
  AND token = 'bRQZgNgtyM4Sqo9Oo/qkHZXWcUBJyjyhYdmVwwFKHfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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