SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbd228d68a20b79229d75d24a2c720dd9e3ccad9c138bc30af45c8d1f08f3b14' 
  AND token = 'IwICDSOpASrLJFHgoF0CDp3kovFwqWwwByImQj5+/Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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