SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '340bab953d33d318c5781522ea28fa00730c4f1ae91f91c2c86e7174a488b604' 
  AND token = 'tFYOCmdX8v9gPAS+BogGEmutu/h9lhIMp7BExjHClWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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