SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cec73b68fd03ec37d8cbdb99ac8dc971c7ad895d6966bd1166d32cc03133326' 
  AND token = 'MUTvVPngZqEMB+axrdfhISElAtgbs9zL7Bh+HC7Laps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}