SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b20ba5789ee8d4caa5d0d658fecd0ad09ed3fff06951b33add983a036522527a' 
  AND token = '1OPQXS4n/ZdvCjQzNF9w1rcJmZYTuW/0BAzZaOLnHvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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