SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '941292e683c9a748734195ff5d51722e4c3098d48fc349687b071c4ddc122535' 
  AND token = 'ToUrwTNdpqAVr6gqL1iAzijvj64FlxRcpQCv5hUCPrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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