SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd1f8be1cd34b59ce524ef375fd32b70f87fdce97b929610c4bcadabcaae745b3' 
  AND token = 'sAV52fzNlABpUhSDzE5qTi32mgEM/SPTnXhAGlTpp58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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