SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49a4e41bc5f2f4c593175c0b67340f4f0068b2a28c4561d181da34da5c8f3957' 
  AND token = 'kYdbtmgG4Q5Bfjj//9uJKmYcZUWO/WwQOC73wEAph2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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