SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '80479646791b7e5a6f6855d093d4e29823f626fc99dd5724a3dd1b11c52dd719' 
  AND token = 'bM5hmm+OmR6mR9VAUU4hod+/3s7F7sxcFR4d3kC8fmM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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