SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12a383f326403b3a43d3705c4380fd68efa4c4924e7bc2d2d87854529ebbcb6f' 
  AND token = 'KkhLQjQD2fiLUpXyeaYPCxpWXj7dtg0IZP+4amL92OY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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