SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4671af6354504c9adc25c1acf090573ce891d92036dbd21a728d953c4135ef96' 
  AND token = 'QX1CAdo33mwXyfRcyM82BCtpJemEocJgjhlpqfHTiwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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