SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fe3de16a0cbc4a4d0433d40d6e8cf1875de02b0e4f5f94c31fe8a128159d706' 
  AND token = '3qv4KP9QgLNlXdxhIivEww/JtB89DaLoLWhl2n+Hj7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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