SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f25b540262f4e3857834b381f4fa975d15c8099891c9913ef4c6343e08b2e7c4' 
  AND token = 'uphTS32KKLmVWS0lAosTWiAPQJDOGvdIPhgpzKmOFQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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