SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f2209872b05280480bb664731ea0d4776337209efb9d902492698aa056e9a2b' 
  AND token = '1NqjQdcU4aJLWskisucNYDS5aB1umqQ1sUg3OIGyGps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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