SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b4863768d895badd320dbe93b3cdcc27824fe0e354c805ae2f37af10984308c' 
  AND token = '7t0waCtKGkRQkAAIJr5CGRjMoA70RRA1JvUsmHySCzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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