SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83344681a6d2b0b8c3b2b36fec4fe760980de4ddbf0584761477aa7f219c8cf1' 
  AND token = 'HQXwws2nfvs7tmcNm1hCoZjeDInRt5aAzcqISHLpgPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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