SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56e99ba888f5184c0285e0a62b4d29c624b5a021c878f9312335aaa66254c51c' 
  AND token = 'vbrBcdRTxwVNCXIHevQWmQ1njZLfAVcrPgFo7SuOHhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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