SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3221f3dd76d3d334c8101972e9be988ae0b5809c2c751e8405f3c0875469bd2' 
  AND token = 'eFzXJcRO5sPTsPDgMrdo8FL8SWETjZT8SSfjdxSf7p0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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