SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ded09bb0d4504fa3f3f867f461a991d92a047f212243833b0aba3821dbfe96' 
  AND token = 'T9wPLdBEqQ9CGgYZ/JoHihmMwzqRHCCvhg85E+vBLRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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