SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec82b4aff75d05e0239b91052374622a0b02905d354b6e2b5e73be18f04607c3' 
  AND token = 'QYuCZ+TtwJqhCmVnMU+OB73yP/z2tUYRwFhi9PVvuvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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