SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54dbeb3dbd06dc6e685ba4c06a105466f3d7190d0195dad88a023478c006bb21' 
  AND token = 'VcOSEJJPDsaGso3NDl3IDBk2qyjS/ROaxhs6TQU29/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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