SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c29bf24efd4594b6b8bd2192faade52fe26a3a974d50b86e8ae6a137bc63f31b' 
  AND token = 'nljjJa1uqgO7ulwT+uL9xIVnwcPbzICUMd8we5GEvRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}