SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27a66dd6ae63095ad21173c4b3db73f90435c7aa1a33e7477dd5d7850a16e16b' 
  AND token = '1cLrk/4QtMcj8QBR64zfwJXCSIXFjvl2cgw/SI6xl7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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