SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c254e7b0690ff2bc11809f71383feff6d0749cd276263bf4ee4f419d9454f10a' 
  AND token = '8t3GfoiETCnJ2Hch5VBZVOr6LyJUXi5G81hjyQxgB9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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