SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af55c8ad5d15cb7ce987991fe2fb594aaf69c91bf04366140a001544baf6beb0' 
  AND token = 'jgLuKJaIc0mSzAhsPLF0Xw5Z+RUccVeD0JpcZuLSYFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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