SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ec22db73d4ebdfa7558a080a0935ad5e09af20e4f60a753b872277134dc8b6b' 
  AND token = 'iQrhwJl7Gb/0VgLzt+rEjLwIrEzWhUCOMD8q75Htouw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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