SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6c27fd701071e9c086979034196b138010f62800a36a0ea0c9025d91d5289dd' 
  AND token = 'dkLsI1VrydkhZhZ0WbM0Bw/BzOgG3VYyPZdP7w+mudg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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